Preheat oven to 375 degrees. Start by whisking together the flour, baking soda, sea salt, and cinnamon in a medium bowl. In the bowl of a mixer, cream together the butter, white sugar, brown sugar until the mixture is light and fluffy. Add eggs and vanilla and mix until blended.
Slowly add the flour mixture, with the mixer on low speed, until it's just combined. Fold in the chocolate chips and mini marshmallows.
Line a baking sheet with parchment paper and laying graham cracker squares side-by-side. Put a scoop (a little more than 1 tablespoon) of dough in the middle of each graham cracker and press down lightly with your finger. Put the baking sheets in the oven and bake for about 5 minutes. Remove from oven and place Hershey's chocolate pieces on top of each cookie. Put the cookies back in the oven for another 5-7 minutes, until edges are golden.
Cool a bit in the pan and then move to wire rack to cool completely. Cut cookie bars with a sharp knife and keep in airtight container for up to five days (if they last that long).
Recipe by In Good Taste at http://ingoodtaste.kitchen/smores-cookie-bars/